Latch mechanism



Oct. 8, 1957 R. MAINHRDT LATCH MECHANISM Filed Sept. 13, 1954 f Tamil.. ,/5

United States Patent iiice 2,809,062 Patented Oct. 8, 1957 LATCH MECHANISM Robert Mainhardt, Diablo, Calif. Application September 13, 1,954, Serial No. 455,700

1 Claim. (Cl. 292-144) This invention relates to locking or latching elements for releasably securing a movable member, such as a door, Window or drawer, against movement relative to an adjacent frame or support member, and is more particularly directed towards a novel arrangement for selectively placing the lock element in its operative and inoperative positions.

It is an object of the present invention lto provide a latching mechanism for doors, windows, drawers or the like in which an internal bolt element may be axially moved to either a locking position or a released position from exteriorly of the structure Without requiring any mechanical operation such as knob or key rotation, and without necessitating any complicated installation for the mechanism.

Another object of my invention is to provide a lock arrangement of the character described in which a magnetic force is utilized for effecting movement of the latch or bolt in which the presence of the lock is completely unapparent from other side of the door.

A further object of this invention is to provide apparatus as above describedjin which means may be incorporated so that the aforementioned axial bolt movement may be affected from only one side of the structure, thereby permitting the use of such apparatus on windows or the like Without danger of unauthorized opening from the outside of the structure.

A still further object of this invention is to provide a mechanism as hereinabove characterized which may be readily placed on cabinets, windows, doors, drawers, etc. to prevent children or other persons from opening the particular structure, with all of such installations being operable by a single magnet capable of attracting the ferreus bolt, or by a bar of ferrous metal capable of actuating a magnetic bolt.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of the preferred form of the invention which is illustrated in the drawing accompanying and forming part of the specification. It is to be understood, however, that variations in the showing made by the said drawing and description may be adopted within the scope of the invention as set forth in the claim.

Referring to said drawing:

Figure l is a cross-sectional View of a portion of a door and frame structure equipped with the latch of the present invention, the latch being illustrated in its open or inoperative position.

Figure 2 is a view similar to Figure 1, but showing the latch in its closed or operative position.

Figure 3 is a cross-sectional View of a modified form of the invention.

Figure 4 is a perspective view of a bracket shown in Figure 3.

Figure 5 is a view similar to Figure 1, illustrating another form of lock arrangement.

Figure 6 is a cross-sectional view of still another form of the invention.

Figure 7 is a cross sectional view of a further form of the invention.

Before discussing the details of construction and operation of the present mechanism, it will be noted that the drawing, for reasons of simplicity, shows the same in connection with a door and adjacent frame structure. However, it will be apparent that the same arrangement is equally effective on windows, drawers or other structures wherein a movable member is to be releasably secured to a relatively stationary member.

Referring rst to the embodiment of the invention shown in Figures l and 2 of the drawing, a portion of a .door 12 is shown in its closed position relative to a stationary frame or jamb portion 13, and as will be understood, the door is movable about hinges or the like as suggested by the arrow in Figure l. In order to maintain the door in its closed position, the lock mechanism of the present invention is utilized. As here illustrated, such mechanism will be seen to include a bolt member 14, preferably of elongated cylindrical form, which is axially slidable in a sleeve 16 mounted in a bore 17 of the door. The sleeve is suliiciently long to receive the entire length of the bolt so that the bolt may assume the inoperative position illustrated in Figure 1 wherein 'the door is free to move relative to its frame. In order to lock the door, the frame or jamb is provided with a f bore 18 of Va larger diameter than but axially aligned with bore 17 when the door is shut. A sleeve 19 is mounted in bore 18 and as illustrated in Figure 2, when the bolt is moved to the left, a portion thereof will enter sleeve 19 and eectively prevent relative movement between the members 12 and 13.

VWhile the foregoing construction is not particularly novel, the manner ofV effecting the axial bolt movement constitutes an important feature 'of my invention. In accordance with this invention, I have completely eliminated the need for knobs, keys, and associated mechanisms, and control the bolt movement by magnetic forces. More particularly, the bolt elementy 14 is constructed of a ferromagnetic material such as iron, steel, nickel or cobalt, with the sleeves 16 and 19, as well as the members 12 and 13 being constructed of a paramagnetic material. By way of example, if the members 12 and 13 are formed of wood, the sleeves may be formed of brass, copper, plastic material or other metals which exhibit virtually no properties of attraction, repulsion or magnetization when placed near a magnet or in a magnetic field. Thus, with the foregoing in mind, it will be apparent that by moving a magnet 21 along the axes of the sleeves adjacent the outer faces 22 and 23 of the jamb and door, the bolt will be correspondingly moved to selectively lock and release the door. By using a relatively strong permanent magnet, such as alnico, permalloy or hipernik, I have found that the bolt may be readily actuated through approximately one-half inch of paramagnetic material such as wood, plastic, etc.

The foregoing type of latch arrangement has been found highly satisfactory where, for example, the front of a ycabinet or bureau is not provided with a locking mechanism or where there would be a disadvantage in having any portions of a lock mechanism Visible from exteriorly of the cabinet. Also a child could be readily restrained from opening a door or drawer where dangerous substances may be contained, and the magnet or unlocking key can be stored in a convenient though inconspicuous place when not being used.

I also -contemplate that the bolt 14 may be constructed of a permanent magnetic material, such as alnico, so that a mere piece of iron or steel could actnate the same. However, a horseshoe type magnet used exteriorly on a steel or iron bolt has been found more effective and positive in action. Also if a horseshoe magnet is used in l an automatic locking is desired upon door closure.

conjunction with a magnetized bolt, it would not be necessary to require linear movement of the magnet. The mere application of the appropriate pole of the magnet to the appropriate pole of the bolt will produce the required movement of the bolt. Likewise, by using a diamagnetic material such as Ycopper for the bolt, there would be a repelling action when approached by a magnet.

Means may be provided for preventingcomplete Withdrawal of the bolt from sleeve 16, such as by using a lug 26 or inwardly struck portion on the sleeve engageable in an axial slot 27 of the bolt. The lug may be screwed cr knocked through the sleeve after insertion of the bolt therein and the entire assembly may then Ybe installed in the bore provided therefor.

In place of sleeve 19 on the door jamb, an angle bracket .31, best illustrated in Figure 4 may be utilized. The bracket has a pair of tlanges 32 and 33, with the latter provided with an axial slot 34, and may be installed as shown in Figure 3 in a notched portion 36 of the jamb with ange 33 directly opposed to bore 17 when the door is closed. Flanges 32 and 33 together with wall 38 of the notch provides a receiving cavity for the bolt and the slot permits ready adjustment of the bracket along the notched portion, it being understood that a wood screw 39 is used to hold the bracket in position. Here again, the bracket would be constructed of a paramagnetic material.

In Figure 5, another modication is illustrated where The construction may be the same as that shown in Figures l or 3, except that a spring 41 is positioned in the door bore to bear against the innermost end of the bolt. Also, the striking end of the bolt would be beveled as shown at 42 to assist the same in readily entering the jamb opening upon door closure. Here again, a magnet is `used to move the bolt against the spring pressure to permit withdrawal thereof from the jamb opening and subsequent opening of the door.

Figure 6 illustrates a still further embodiment, particularly well adapted to permit actuation of the bolt only from one side of a structure. For example, on a window, it would not be desirable to permit magnetic control of the bolt from exteriorly ofthe building. Accordingly, on one side ofthe bolt, I place a strip or piece 46 of iron, steel or other ferromagnetic material. Thus, a magnet positioned adjacent the faces 22 and 23 would actuate the bolt without interference, while the magnet placed adjacent the opposite faces 47 and 48 could exert no magnetic force on the bolt and hence would be ineffectual in moving the same.

In Figure 7, I have illustrated an arrangement particularly suitable for installations where the surfaces 22 and 23 of the frame and door are not in coplanar relationship. In this instance the magnet cannot be moved along the door and frame, and therefore, the bolt 14 is made of magnetic material so that one end thereof, e. g., the north 'pole may be positioned in one member to be selectively inuenced by the north or south pole of a horseshoe magnet. As shown in the drawing the bolt has been moved into locking position by the repelled movement of the bolt when the two north poles were brought into adjacent relationship. By merely rotating the horseshoe magnet through 180 degrees and bringing the south pole into such position, the bolt will be moved to its unlocked position.

It will also be understood that in many instances it may not be desirable to drill holes in the members for receiving the bolts, and in such instances suitable apertured brackets could be utilized on the inner faces of a drawer, door or thelike.

Iclaim: Y

A latch mechanism for mounting in a member having a bore therein extending to an edge of said member, including a sleeve made of paramagnetic material disposed within said bore, a generally cylindrical latch element axially slidable in said sleeve from a first position entirelywithin said sleeve to a second position extending outwardly lof said sleeve and said edge of said member, Vsaid element being formed of a permanent magnetic material and having aV north and south pole for influence by an exteriorly placed magnetic force, and a strip of ferromagnetic material is positioned between a surface of said member and said sleeve whereby actuation of said element may be aiected only by application of a magnetic force on another surface of the member.

References Cited in the le of this patent UNITED STATES PATENTS 537,746 Boyum e Apr. 16, 1895 1,933,736 Ingersoll Nov. 7, 1933 2,153,088 Knell Apr. 4, 1939 2,468,969 Galey c May 3, 1949 FOREIGN PATENTS 145,325 Germany Nov. 25, 1903 981,307 France Jan. 10, 1951 

